Radio transmitting system



Dec. 1924. r 1,517,816

E. F. W. ALEXANDERSON RADIO TRANSMITTING SYSTEM Filed June 24, 1921.EI'nsLEWAIeXQndei-SQn;

b3 fl -W4 HisAtborne ERNST E. W. ALEXANDERSON, SCHENECTADY, NEW YORK,ASSIGNOR 'EOGEN ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

RADIO TRANSMITTING SYSTEM.

Application filed June 24, 1821. Serial No. B0,218.

To all whom it may concern:

Be it known that I, ERNST F. W. ALEX- ANDERSON, a citizen of the UnitedStates, residing at Schenectady, county of Schenectady, State of NewYork, have invented certain new and useful Improvements in RadioTransmitting Systems, of which the following is a specification.

My present invention relates to radio transmitting systems, and moreparticularly to systems of the directive type.

The object of my invention is to provide a simple and eflicient systemfor transmitting radio signals which will be adapted for high speedtelegraphic communication or for radio telephony.

When a large amount of power is employed for transmitting purposes, acertain amount of time is required for charging the antenna to its fullpotential. After the power is applied and interrupted the antenna willcontinue to oscillate for some time by reason of the energy stored uptherein. By reason of these facts the speed of the signal when theantenna is employed for radio telegraphy may be somewhat limited becauseof the slow building up and the slow dying down of the potential of theantenna. When the antenna is employed for radio telephony these samefactors interfere with the effective modulation of the energy in theantenna.

In carrying my invention into efiect, I overcome these disadvantages byproviding a transmitting antenna which is made up of two separate partsand supplying energy to both of these parts continuously. If the twoparts are located at the same point the. currents supplied to the twoparts are of opposite phase so that normally no efi'ective radiationwill take place. When'signals are to be' transmitted the phases of thecurrents will be shifted so that they will be approximately in phase andmaximum radiation will be produced. If on the other hand the radiatingsystem is divided into two distinct portions which are separatedgeographically by a distance .which is at least an appreciable fractionof a wave length, then when signals are not being transmitted the phaseof the currents supplied to the diiferent portions of the antenna issuch that the radiation in the direction toward which it is desired totransmit signals is a minimum. When it is desired to transmit .markeddirective properties.

signals the relative phase of the difierent currents is varied so thatthe radiation in the desired direction becomes a maximum. As a result ineither case full energy is supplied to the antenna at all times andnotime is lost in the building up of full voltage on the antenna or in thecutting down of the antenna voltage to a minimum as it is poss ble tovery quickly shift the phase of the dlfferent currents.

The novel features which I belive to be characteristic of my inventionare set forth in the appended claims. The invention itself, however,both as to its organization and method of operation will best beunderstood by reference to the following description taken in connectionwith the accompanying drawing in which I have indicated dlagrammaticallyone way in which my invention may be carried into effect.-

As indicated in the drawing, the radiating system is made up of twomultiple tuned antennae 1 and 2, each provided with a plurality ofground connections 3 and individual tuning coils 4. These antennae maybe close together or parallel to one another or they may be of suchlength and their centersof distribution separated to such an extent soas to produce a radiating system having Energy is continuously suppliedto the. radiating system by means of a'high frequency alternator, whichin the present case is indicated as a quarter phase machine 5, through acommon ground connection 6. Associated with the supply leads 7 and 8 tothe antennae 1 and 2 respectively I provide magnetic amplifiers 9 and10. These magnetic amplifiers are coupled to the supply leads by meansof coupling transformers 11 and 12. Current for saturating the cores ofthese magnetic amplifiers may be supplied to the saturating windings 13and 14 from a direct current source 15 by means of a telegraph key 16having contacts at 17 and 18.

In the case indicated, in the normal position of the key, contact 17 isclosed and the core of amplifier 10 is saturated. When the key 16 isoperated contact at 17 is opened and contact at 18 closed, the core ofamplifier 9 thereby becoming saturated and the core of amplifier 10desaturated.

It now, for example, the centers of distribution of the two antennae area half wave length apart and the two portions are de is changed inopposite irections' The pro- 7 tuned so that the currents in the twoantennae have a phase difl'erence of 180, theradiation from the antennaewill be a maximum in the direction of their length and there will besubstantially no radiation in a direction at right angles totheirlength. When the key 16 isjoperated the tunin of the two antennaeportions of the system may be arranged so that when the key is'closedmaking contact at 18 the currents in the two portions of the radiatingsystem are substantially in phase. The direction of the maximumradiation will then be shiftedand the radiation will'be a I inthe'direction of. their length.

In case it is desired to employ the-radiating system for radiotelephonythe same arrangement maybe employed, the tele phone current which is tobe transmitted being suppliedto the saturating windings in such a waythat it opposes vthe eti' ect of the.

steady D. 6. current in one winding and assists the steady D. 6. currentin the other winding. The direction of maximum radiation will then bevaried in accordance with variations in the telephone current so thatthe effect at a distant station in a desired direction will be the sameas produced when "the current transmitted is modulated in the,

usual way.

What I claim as new and desire to secure by Letters Patent ofthe UnitedStates, -is,:

1. The method of operating a directive radio transmitting system totransmit signals which consists in continuously supplying energy to theradiating system and varying the phase of the currents supplied to thedifi erent portions of the system in such a way as to vary in a desiredmanner the direction in which the radiation will be a maximum.

2. The method of operating a directive radio transmitting system totransmit signals which consists in continuously supplying currents ofdifferent phase to different portions of the radiating system andvarying the relative phase of the differentcurrents in such a way as tovary in a desired manner the direction in which the radiation will be amaximum.

3. The method of operating a directive radio transmitting system whichconsists in continuously supplying currents of different phase todifferent portions of the radiating system which are separated by anappreciable fraction of a wave length and varying the relative phase ofthe difierent currents in such a way that when signals are to betransmitted the radiation in a desired direction will be a maximum andat other times the radiation in that direction will; be a m imum 4a Themethod of operating a directive preciable fraction of a'vwave length,the

phase of the dilferentcurrents normally supplied being so adjusted withrespect to the separation of the different portions of I. I

the radiating system that the radiation in a desired direction will. bea minimum, and varying the relative phase of the currents whensignalsare to be transmitted so that the radiation 'in-the' desireddirection will be a maximum.

. 5. The method of operating a radio'transmitting system which consistsin continuous: I

ly supplying currents of difl'erent phase to j difi'erent portions oftheradiating system,

and varying the relative phase of the dit-u ,terent currents in such away as to produce in accordance with signals a desired variation in thedirection of the effective radiation. V v '6. The method of operating.alradiotransmitting system wh ch consists in continuous- I 1y supplyingenergy to the radiating system and varying the relative phase of thecurrents flowing in differentparts of the radiating system :in'such away as to produce in accordance with signals a desiredvariation in thedirection of the effective radiation.

7.'The combination in a radio transmitting sys em of a source of radiofrequency,

.means' .for continuously supplying energy from said source toaradiating system, and means for varying the relative phase of thecurrents flowing in different parts of the radiating system in such away as to pro- -duce in accordance with signals a desired variation inthe direction of the effective radiation.

8; The combination in a radio transmitting system of a source 0t radiofrequency energy from which currents of different phase may be obtained,a radiating system comprising two portions separated by an appreciablefraction of a wave length, means for continuously supplying separatecurrents from said source to the different parts of said radiatingsystem, and means for separately and simultaneously varying inaccordance with signals the phase relation of the differentcurrentssupplied to the different parts of the radiating system.

9. The combination in a radio transmitting system of a source of radiofrequency energy from which separate currents of different phase may beobtained, means for continuously supplying from said source separatecurrents to different portions of a radiating system, and means forvarying the phase of the currents supplied to the different portions ofthe system in such a way as to vary in a desired manner in accordancewith si nals the direction in which the radiation wi I be a maximum.

10. The combination in a radio transmitting system of a source of radiofrequency energy from which separate currents of different phase may beobtained, means for continuously supplying from said. source separatecurrents to different portions of aradiating system, and means forvarying the relative phase of the different currents supplied to thedifierent portions of the system in such a way as to produce inaccordance with signals, a desired variation in the direction of theeffective radiation.

11. The combination in a radio transmitting system of a source of radiofrequency energy from which separate currents of different phase may beobtained, means for continuously supplying from said source separatecurrents to diflerent portions of a radiating system which are separatedby an appreciable fraction of a Wave length, and means for varying thephase of the currents supplied to the different portions of the systemin such a way that when signals are to be transmitted the radiation in adesired direction will be a maximum and at other times the radiation inthat direction will be a minimum.

12. The combination in a radio transmitting system of a source of radiofrequency energy from which currents of different phase may be obtained,a radiating system comprising two separate portions separated by anappreciable fraction of a wave length, means for continuously supplyingseparate currents from said source to the different parts of saidradiating system, and means for separately and simultaneously varyingthe phase relation of the different currents supplied to the differentparts of the radiating system so that when signals are to be transmittedthe radiation in a desired direction will be a maximum and at othertimes the radiation in that direction will be a minimum.

13. The combination in a radio transmitting system of a source of radiofrequency energy from which currents of difierent phase may be obtained,a radiating system comprising two separate portions, means forcontinuously supplying separate currents from said source to thedifferent parts of said radiating system, and means for separately andsimultaneously varying the phase relation of the different currentssupplied to the different parts of the radiating system in such a way asto produce in accordance with signals a desired variation in thedirection of effective radiation.

In witness whereof, I have hereunto set my hand this 23rd day of June,1921.

ERNST F. W. ALEXANDERSON.

